+// OSX is a pain. The XCode 8 SDK always declares clock_gettime
+// even if the target OS version doesn't support it, so you get
+// an error at runtime because it can't resolve the symbol. We
+// solve that by pretending we have it here in the header and
+// then enable our implementation on the source side so that
+// gets linked in instead.
+#if __MACH__ && \
+ (MAC_OS_X_VERSION_MIN_REQUIRED < MAC_OS_X_VERSION_10_12 || \
+ __IPHONE_OS_VERSION_MIN_REQUIRED < __IPHONE_10_0)
+
+#ifdef FOLLY_HAVE_CLOCK_GETTIME
+#undef FOLLY_HAVE_CLOCK_GETTIME
+#endif
+
+#define FOLLY_HAVE_CLOCK_GETTIME 1
+#define FOLLY_FORCE_CLOCK_GETTIME_DEFINITION 1
+
+#endif
+